The process for harvesting, curing, and storing sweet potatoes is simple once you get the hang of it. Here’s how to do it.
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Growing Sweet Potatoes
Sweet potatoes are one of my absolute favorite crops to grow. They’re generally pest-free and low-maintenance: plant them late in spring and expect a yield – no matter how the growing season went – by the time fall rolls around. They like it sunny and hot, and watering isn’t essential.
This year was cooler than usual for us and that affected our yield, but with no regular maintenance required for this crop, I’m not complaining.
Sweet potato vines also produce well when trellised, because vines scaling the ground will try to put roots in everywhere, which produces a gazillion teensy little potatoes as opposed to several big ones per vine.
Harvesting Sweet Potatoes
Sweet potatoes can be harvested any time tubers have formed (start checking late summer). I’ve found the best strategy is to let them stay in the ground a little while longer, since they’ll continue to grow until a hard frost takes them out.
The key to a superior, sweet taste is allowing them to experience a light frost, and then harvest before the hard frost.
For harvesting, pick a harvest day when it hasn’t rained for a few days. The soil should be minimally moist and crumbly so that you can brush most it off the tubers with a very light touch. You don’t want mud caked onto the tubers because it will make them hard to clean and store.
The harvesting process starts with cutting the vines back so you can get to the soil. If you’ve grown your sweet potatoes on a trellis, then the vines will only be attached at the original root location, which makes it easier to guess where the tubers developed underground. I cut the vines leaving 6 inches above ground to help me locate my treasure.
The next step is a delicate one. At this stage, the skins of the sweet potato are very thin and easily damaged. I use my soil knife to carefully and slowly push away the soil to reveal the harvest treat. Then I use the knife to loosen the soil around it, and dig under the tuber, lifting it out gently.
Whether you’re using a knife or a shovel for harvesting, don’t aimlessly stab into the soil, as you’ll risk cutting the tubers in half. Once you’ve found one, don’t pull it out, because the delicate gems will undoubtedly snap in half, leaving the other half buried.
Pieces of tubers won’t store as well as whole, unscathed potatoes. So dig gently, find a tuber, loosen and lift. Having loose soil really helps, so consider growing yours in a raised bed.
By the way, learning to use a soil knife was one of the best lessons I learned from my old gardening boss and mentor. I still have the one she bought me–my own special left-handed one. It still looks like new today, so it’s a tool that keeps its value.
Don’t forget to cover your garden bed with shredded leaves for wintertime protective mulch and springtime compost!
You’ve harvested your sweet potatoes and now you’re thinking that you’ll head to the kitchen and make a sweet potato casserole, right? Wrong. Sorry, but the maintenance of growing sweet potatoes–unlike most other vegetables–comes post-harvest.
Curing Sweet Potatoes
Sweet potatoes must be cured for about 10 days. This will heal any damage that occurred to the tubers during harvest so they store longer, and it will also kick off the sugar production process to give you sweeter sweet potatoes.
How to cure? The ideal is an 85-degree room with 85% humidity. What? You don’t have that?!
My easy solution for years running now is this: take plastic grocery bags, punch some holes in them, and fill them with sweet potatoes enough so that there is just one layer of them in each bag. Tie the bags closed and put in your sunniest, warmest window. Leave it for 10 days.
If it gets chilly and your windows are drafty, put a blanket or towel over them when the sun isn’t shining.
Storing Sweet Potatoes
Open your plastic bags of curing sweet potatoes after 10 days. They should be moist and much harder to the touch. If there are any soft ones, these should be tossed out. Now, take single sheets of newspaper and roll up each tuber separately. Stack the wrapped sweet potatoes in a cardboard or wooden box of your choosing (or one that allows aeration), without a lid, and place it in a basement or other room where the temperature is as close to 55-60 degrees as possible, for 6 weeks.
This will even further develop the hard skin and kick off even more sugar production. The newspaper allows aeration and prevents moisture build-up that would otherwise ruin the crop.
After 6 weeks, you can FINALLY cook with them and know that they are at the peak of their sweetness, or you can store them for up to 6 months with the lid on the box, or in a spot not exposed to sunlight. The length of time they store will depend on the degree to which the storage conditions are ideal: temperature (55 degrees), no light, and around 60% humidity.
So this means that if you want to serve that sweet potato casserole at Thanksgiving, you’ll want to harvest your sweet potatoes in early October at the latest. You may not get that frost-kissed sweetness, but the curing process will help sweeten them up.
The process for harvesting, curing, and storing sweet potatoes sounds complicated and time-consuming, but really it’s simple once you get the hang of it. The taste of these homegrown, sweet orange gems that say ‘Thanksgiving’ will be all you need to convince yourself to grow them year after year.
Need more ideas for growing vegetables in the permaculture garden?
- Growing & Harvesting Beets Year-Round
- Protect Cold Weather Crops with a Cold Frame
- When to Harvest & How to Store Garlic
Are you looking for more strategies for your permaculture garden? You’ll find loads of information just like this in my book, The Suburban Micro-Farm.
Are sweet potatoes one of your favorite crops?